Prime Minister David Cameron has apologised to the families of the Hillsborough victims, saying: "What happened that day, and since, was wrong".
Cameron, delivering a statement to the Commons after the publication of a report by the Hillsborough Independent Panel, said police and emergency services made "strenuous attempts'' to deflect the blame for Britain's worst-ever sporting disaster, in which 96 people died, onto fans.
He said there had been a "failure of the state" to protect the relatives' loved ones.
"The new evidence that we're presented with today makes clear, in my view, that these families have suffered a double injustice: the injustice of the appalling events, the failure of the state to protect their loved ones and the indefensible wait to get the truth, and then the injustice of the denigration of the deceased - that they were somehow at fault for their own deaths," he told MPs.
"With the weight of the new evidence in this report, it is right for me today as prime minister to make a proper apology to the families of the 96 for all they have suffered over the past 23 years.
"So on behalf of the government, and indeed our country, I am profoundly sorry that this double injustice has been left uncorrected for so long."
A Liverpool FC statement said: "After 23 long and painful years, our fans have finally been fully exonerated of all blame. Today, the world knows what we have always known - that Liverpool fans were not just innocent on that terrible day but that there was also reprehensible and hurtful misrepresentation of the truth."
The panel that compiled the report, which was chaired by the Right Reverend James Jones, the Bishop of Liverpool, assessed more than 400,000 pages of documents relating to the 1989 FA Cup semi-final disaster. The report's findings were made available to relatives from 8am on Wednesday.
Cameron said the document revealed that 164 police statements had been "significantly amended", with comments attacking the conduct of officers removed from 116 of those. For the first time, it disclosed that South Yorkshire Ambulance Service documents had been "subject to the same process''.
The report said that, at a Police Federation meeting, South Yorkshire Police had been advised to prepare a "defence" and a "rock-solid story" and told that "drunken ticketless individuals" should be blamed for what had happened.
Cameron said the report showed that police had carried out checks on victims in an attempt to "impune their reputations", adding that the then government, led by Margaret Thatcher, should have done more to challenge the falsehoods being spread about the Liverpool fans.
However, he insisted there was no evidence that the government had attempted to conceal the truth.
Describing the report's findings as "deeply troubling", he said it was "black and white" in proving that Liverpool fans had not been responsible for the disaster and that there had been a concerted attempt by police to divert the blame.
The PM told the Commons that newspapers - most infamously the Sun - had reported false allegations about the behaviour of supporters.
The report showed that briefings to the media, which led to the Sun's story, had used information from a Sheffield news agency that reported comments made by police officers. Kelvin Mackenzie, the editor responsible for headlining that story 'The Truth', issued an apology after the panel's report was published.
MPs were told that some of those who died on the terraces at the Leppings Lane end of Sheffield Wednesday's ground had suffered reversible asphyxia and could have been saved, but the report showed there had been serious shortcomings in the response of the emergency services.
Neither Lord Justice Taylor, in his report soon after the disaster, nor the coroner at the original inquest, had looked properly at the response of the other emergency services, the Commons heard.
The report found that the ambulance service failed to implement its major incident plan fully and that there had been "a delay from the emergency services when people were being crushed and killed''.
Cameron said the original inquest into the deaths - which said all the victims had died by 3.15pm, 15 minutes after the match had kicked off - was inadequate. The report called the original pathologists' evidence of a single, unvarying pattern of death "unsustainable''.
The attorney general, Dominic Grieve, must now decide whether to apply to the High Court to overturn the verdict of that inquest and order another one.
The report also said the risks at Hillsborough were known, and that there had been dangerous situations in the stadium in 1981, 1987 and 1988 and the safety of the crowd in 1989 had been "compromised at every level".
"Not enough people in this country understand what the people of Merseyside have been through," Cameron said. "This appalling death toll of so many loved ones lost was compounded by an attempt to blame the victims."
The Labour leader, Ed Miliband, said it "shamed the country" that it had taken 23 years for the truth about what happened that day to emerge and called on Cameron to ensure that Grieve acted with urgency.
Miliband said there had been "terrible mistakes and negligence in policing", and added: "There was a systematic attempt by some in the police to cover this up after the event and, disgracefully, to spread the blame to the fans. They were aided and abetted by parts of the media."
He said it was "clear that the original inquest was hopelessly inadequate" and asked whether those responsible for the conduct of police at the time could be held accountable.
Steve Roterham, the MP for Liverpool Walton, said the families of the 96 "finally have the undeniable truth", while Sheila Coleman, of the Hillsborough Justice Campaign, said: "We have had the truth - now it is time for justice.
"Clearly, people indulged in criminal activities by changing and altering statements and telling lies. If you or I did that, we would be prosecuted - people cannot be above the law. The law-makers and those who are supposed to uphold the law shouldn't be above the law."